Matweb is Your Online Resource for Material Data Sheets

Matweb is an online database consisting of over 77,000 material Data Sheets. Their searchable database of material properties includes data sheets of thermoplastic and thermoset polymers such as ABS, nylon, polycarbonate, polyester, polyethylene and polypropylene; metals such as aluminum, cobalt, copper, lead, magnesium, nickel, steel, superalloys, titanium and zinc alloys; ceramics; plus semiconductors, fibers, and other engineering materials.

A quick search for "Polycarbonate" gave over 4300 results. If you're in need of data sheets, this is the place to find them.